eng Science and Education Publishing American Journal of Medical Case Reports 2374-216X 2020-01-16 8 3 70 72 10.12691/ajmcr-8-3-1 AJMCR2020831 article Ziad SayedAhmad ziad.sayedahmad@health.slu.edu 1 Zachary Oman 1 Ihab Hassanieh 1 ElSayed Abo-Salem 1 Tarek Helmy 1 The Center for Comprehensive Cardiovascular Care, Department of Cardiovascular Medicine, Saint Louis University School of Medicine, Saint Louis, Missouri Atrial arrhythmias have been associated with a large number of medical conditions such as infection, chronic obstructive pulmonary disease, pulmonary embolism, hyperthyroidism, hypertension, and acute coronary syndrome to name a few. While less common, atrial arrhythmias have also been associated with disease processes causing pericardial inflammation. As such, presentation of atrial fibrillation/atrial flutter (A-Fib/A-Flutter) as a complication of pericardial effusion and the role of pericardiocentesis have not been well described. We report two cases of large pericardial effusions complicated by A-Fib/A-Flutter with immediate conversion to sinus rhythm following pericardiocentesis. http://pubs.sciepub.com/ajmcr/8/3/1/ajmcr-8-3-1.pdf pericardial effusion Pericardiocentesis atrial fibrillation